locker_statusFree. Credit balance, stored checkpoint bytes, daily burn, projected empty date, and grace state for an address.
| Name | Required | Description | Default |
|---|---|---|---|
| address | Yes | EVM wallet address (0x…, the mailbox identity). |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses that the tool is free and lists the returned data fields, but does not explicitly state whether it is read-only, whether it requires specific permissions, or if there are any side effects. The term 'status' implies a safe query, but this is not made explicit, and no information about error behavior or data freshness is provided.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, compact sentence that front-loads the key fact 'Free' and then lists the returned data points in a readable, comma-separated format. Every word contributes to understanding what the tool does, with no unnecessary filler.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the low complexity (one parameter, no output schema) and the presence of a 100% schema description, the description adequately lists the return values at a conceptual level. It does not detail the exact response format, but for a simple status tool this is sufficient for an agent to invoke it and interpret the high-level result.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema already provides 100% coverage with a clear description of the 'address' parameter. The tool description adds no additional information about the parameter beyond saying 'for an address', which does not enrich the schema. Baseline of 3 is appropriate because the schema fully describes the parameter.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states what the tool returns: credit balance, stored checkpoint bytes, daily burn, projected empty date, and grace state for an address. It is a clear noun-phrase description of a status check, but lacks an explicit verb like 'get' or 'retrieve'. It distinguishes itself from siblings by listing multiple aggregated data points, though it does not explicitly differentiate from similar tools like locker_credit or locker_checkpoint.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no guidance on when to use this tool versus alternatives. The description does not mention any exclusions, prerequisites, or scenarios where locker_credit or locker_checkpoint would be preferred. The usage is only implied by the word 'status', which is insufficient for an agent deciding between sibling tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool has a clearly distinct purpose: send, read, ack, count, register_key, directory, nonce, capabilities, credit, checkpoint, and status cover different operations without overlap. Even similar-sounding tools like count and read are cleanly separated by scope (message count vs. message content).
All tool names follow a uniform pattern with the 'locker_' prefix and lowercase snake_case. While some postfixes are nouns (capabilities, directory, status) and others verbs (send, read, ack), the style is consistent and predictable, matching the server's domain.
11 tools is well-scoped for a messaging/storage server: each tool earns its place covering setup, messaging, payment, and account management without redundancy or bloat.
The tool surface provides complete lifecycle coverage for the mailbox system: key registration, message sending/reading/acknowledging, directory lookup, nonce generation, payment via credit, persistent checkpoint storage, and status monitoring. No obvious dead ends or missing operations for the stated purpose.